Figure 4. Field-scale photographs of Late Oligocene volcaniclastic strata in the Margargaria River localities, northwestern Ethiopian Plateau. 4.1 General view of outcrop showing strata arranged into seven different depositional units (A- cross-laminated sand, B- scour-fill silt and sand, C- massive silt to sand, D- laminated clay to sand, E-massive clay, mud, and sand, F- bioturbated, massive clay to sand, G-lignified/semi-lignified organic matter). Man (Mr. Gebre Meskal) for scale = 175 cm. 4.2 Close-up view of A, C, D, E, F, and G depositional units showing their relative thicknesses, sedimentary structures, and contact surfaces. See text for discussion. Scale bar equals 25 cm. 4.3 Close-up view of C and B depositional units showing their relative thicknesses, sedimentary structures, and contact surfaces. See text for discussion. Tape measure equals 62 cm.